Colloidal Matter, Part 1 - An Introduction

Greetings,

This post begins a series on colloidal matter.  Although the colloidal state seems rather obscure, compared to pure states of matter, in reality many common substances are colloids.  We find colloidal matter in common things such as a car seat, marshmellows, mayonnaise, and milk.  Certain colloids, like jello-o gelatin, appear to be somewhere between two states.  A colloid is a homogeneous mixture of two substances for which one substance exists as tiny droplets (or particles) dispersed throughout the other substance.  The substance existing as tiny droplets or particles is the dispersed phase and the other substance present is called the continuous phase.

Types of Colloids

There are eight different categories of colloids, based on the states of matter present.  This means there are a total of eight combinations of dispersed and continuous phases.  These types of colloids are summarized in the diagram below.

What is missing from the "Types of Colloids" list is a gaseous dispersed phase combined with a gaseous continuous phase; no such type of colloid exists.  As you can see from the extensive list, there are a great many colloids which we encounter in our daily lives.

So there you have it!  The colloidal state of matter is all around us.  The next few posts will feature specific examples of this remarkable state of matter, the colloid!

Thank you for reading!